Heating food in microwave ovens has become commonplace. It is widely recognized, however, that microwave energy fails to impart the proper amount of browning and/or crispness to foods normally expected to possess such a quality. Consequently, these foods, when cooked in a microwave oven, are not aesthetically appealing to the consumer.
Various attempts have been made to improve the browning or crispening of food when employing microwave heating. Such attempts have included incorporating into the microwave oven means to convert the high frequency microwave energy by resistive losses to heat energy. Additionally, edible coatings have been added to the food itself in order to induce browning and crispening and various utensils and dishes have been devised to promote browning.
One example of an apparatus designed to be employed in the microwave oven is shown in the U.S. Pat. No. 3,943,320 (Bowen) issued on Mar. 9, 1976. In this patent, a utensil for heating circular elongated objects such as hot dogs with microwave energy is disclosed. The utensil facilitates the browning and searing of the exterior surfaces of the food product and includes a plurality of searing members of a curved, tapered, substantially v-shaped configuration spaced from one another to encompass a portion of the elongated object to be heated. The searing means are supported on a microwave transparent frame of plastic material.
Another example of a device for use in a microwave oven is the microwave oven toaster disclosed in U.S. Pat. No. 4,748,308 issued on May 31, 1988. The microwave toaster includes a rectangular block of microwave transparent material including a plurality of parallel and aligned slots therein for receiving cards of material which absorb microwave energy and subsequently dissipate heat. In operation, two cards are inserted into two adjacent slots and a piece of bread is positioned between the two cards to absorb the heat dissipated therefrom to subsequently brown the bread.
Yet another example of an apparatus for use in a microwave oven is disclosed in U.S. Pat. No. 4,267,420 issued on May 12, 1981. This patent discloses a plastic film or other dielectric substrate having a thin coating thereon which controls the microwave conductivity when the package is placed in a conventional microwave oven. The plastic film and its coating may be wrapped around the food item and converts some of the microwave energy into heat which is then transmitted directly to the surface portion of the food item to cause browning and/or crispening.
In order to satisfy the needs of contemporary consumers, disposable containers are needed which, when used in a microwave oven, duplicate as closely as possible the cooking results of a conventional oven. Such containers should also serve as a shipping carton and display carton and be sufficiently economical to allow it to be disposable. Paperboard cartons satisfy many of these performance objectives but generally must be designed in accordance with requirements which are dependent on the type and quantity of the food to be placed and cooked in the container.
An example of a paperboard container designed for browning and crisping food is disclosed in U.S. Pat. No. 4,590,349 issued on May 20, 1986. This container includes a paperboard carton for heating and crisping two sides of food pieces having non-uniform dimensions in a microwave oven. The carton includes vertically spaced food supporting panels and a pair of microwave interactive layers associated with corresponding food supporting panels for converting microwave energy into heat for browning and crisping food pieces. The package also includes handles for allowing manual inversion of the container during the crisping and cooking process. This container suffers from several disadvantages, namely that it only browns food on two sides, that it requires inversion during the cooking process and that it is not practical for small food items wherein many units are incorporated in a single package.
Thus, there remains a need in the microwave container art for a cook-in container for foodstuffs and particularly for smaller foodstuffs which require browning and crispening, which is inexpensive, simple to manufacture, disposable and capable of browning substantially the entire surface of the food product.